[settings] Generalise expand_command() to expand_settings()

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/core/exec.c

 	return -ENOEXEC;
 }
 
-/**
- * Expand variables within command line
- *
- * @v command		Command line
- * @ret expcmd		Expanded command line
- *
- * The expanded command line is allocated with malloc() and the caller
- * must eventually free() it.
- */
-static char * expand_command ( const char *command ) {
-	char *expcmd;
-	char *start;
-	char *end;
-	char *head;
-	char *name;
-	char *tail;
-	int setting_len;
-	int new_len;
-	char *tmp;
-
-	/* Obtain temporary modifiable copy of command line */
-	expcmd = strdup ( command );
-	if ( ! expcmd )
-		return NULL;
-
-	/* Expand while expansions remain */
-	while ( 1 ) {
-
-		head = expcmd;
-
-		/* Locate setting to be expanded */
-		start = NULL;
-		end = NULL;
-		for ( tmp = expcmd ; *tmp ; tmp++ ) {
-			if ( ( tmp[0] == '$' ) && ( tmp[1] == '{' ) )
-				start = tmp;
-			if ( start && ( tmp[0] == '}' ) ) {
-				end = tmp;
-				break;
-			}
-		}
-		if ( ! end )
-			break;
-		*start = '\0';
-		name = ( start + 2 );
-		*end = '\0';
-		tail = ( end + 1 );
-
-		/* Determine setting length */
-		setting_len = fetchf_named_setting ( name, NULL, 0 );
-		if ( setting_len < 0 )
-			setting_len = 0; /* Treat error as empty setting */
-
-		/* Read setting into temporary buffer */
-		{
-			char setting_buf[ setting_len + 1 ];
-
-			setting_buf[0] = '\0';
-			fetchf_named_setting ( name, setting_buf,
-					       sizeof ( setting_buf ) );
-
-			/* Construct expanded string and discard old string */
-			tmp = expcmd;
-			new_len = asprintf ( &expcmd, "%s%s%s",
-					     head, setting_buf, tail );
-			free ( tmp );
-			if ( new_len < 0 )
-				return NULL;
-		}
-	}
-
-	return expcmd;
-}
-
 /**
  * Split command line into tokens
  *
 	int rc = 0;
 
 	/* Perform variable expansion */
-	expcmd = expand_command ( command );
+	expcmd = expand_settings ( command );
 	if ( ! expcmd )
 		return -ENOMEM;
 

src/core/settings.c

 	.fetchf = fetchf_uuid,
 };
 
+/******************************************************************************
+ *
+ * Setting expansion
+ *
+ ******************************************************************************
+ */
+
+/**
+ * Expand variables within string
+ *
+ * @v string		String
+ * @ret expstr		Expanded string
+ *
+ * The expanded string is allocated with malloc() and the caller must
+ * eventually free() it.
+ */
+char * expand_settings ( const char *string ) {
+	char *expstr;
+	char *start;
+	char *end;
+	char *head;
+	char *name;
+	char *tail;
+	int setting_len;
+	int new_len;
+	char *tmp;
+
+	/* Obtain temporary modifiable copy of string */
+	expstr = strdup ( string );
+	if ( ! expstr )
+		return NULL;
+
+	/* Expand while expansions remain */
+	while ( 1 ) {
+
+		head = expstr;
+
+		/* Locate setting to be expanded */
+		start = NULL;
+		end = NULL;
+		for ( tmp = expstr ; *tmp ; tmp++ ) {
+			if ( ( tmp[0] == '$' ) && ( tmp[1] == '{' ) )
+				start = tmp;
+			if ( start && ( tmp[0] == '}' ) ) {
+				end = tmp;
+				break;
+			}
+		}
+		if ( ! end )
+			break;
+		*start = '\0';
+		name = ( start + 2 );
+		*end = '\0';
+		tail = ( end + 1 );
+
+		/* Determine setting length */
+		setting_len = fetchf_named_setting ( name, NULL, 0 );
+		if ( setting_len < 0 )
+			setting_len = 0; /* Treat error as empty setting */
+
+		/* Read setting into temporary buffer */
+		{
+			char setting_buf[ setting_len + 1 ];
+
+			setting_buf[0] = '\0';
+			fetchf_named_setting ( name, setting_buf,
+					       sizeof ( setting_buf ) );
+
+			/* Construct expanded string and discard old string */
+			tmp = expstr;
+			new_len = asprintf ( &expstr, "%s%s%s",
+					     head, setting_buf, tail );
+			free ( tmp );
+			if ( new_len < 0 )
+				return NULL;
+		}
+	}
+
+	return expstr;
+}
+
 /******************************************************************************
  *
  * Settings

src/include/ipxe/settings.h

 			    const char *value );
 extern int storef_named_setting ( const char *name, const char *value );
 extern int fetchf_named_setting ( const char *name, char *buf, size_t len );
+extern char * expand_settings ( const char *string );
 
 extern struct setting_type setting_type_string __setting_type;
 extern struct setting_type setting_type_ipv4 __setting_type;